226 naticidjE. 



at Falmouth not only exhibit an irregular style of co- 

 louring, but the last whorl has a tendency to diverge 

 from the one above it in almost a scalariform fashion. 

 The present species differs from N. catena in its smaller 

 size and comparatively greater solidity, more produced 

 and pointed spire, slighter suture, diversified arrange- 

 ment of the coloured markings, and contracted umbilicus. 

 This species was described in the ' Fauna Suecica/ 

 and in the second edition of that work bears the name 

 of Nerita glaucina. It seems to have been mistaken by 

 all the old writers on British conchology for the young 

 of Natica catena. The Nerita nitida of Donovan is a 

 common tropical shell. Indeed he admitted that the 

 authority on which he at first hesitated to insert that 

 species in his work was " vague ; " and his statement 

 that "the same kind was discovered, in the course of 

 last summer, upon the coast of Scotland near Caithness/' 

 is not so satisfactory to me, as evidence that the exotic 

 shell which he figured is British, as it appears to have 

 been to him. In Loudon's Magazine for April 1836, 

 Forbes adopted the name nitida for our shell, believing 

 it to be Donovan's species ; but two years afterwards, in 

 his ' Malacologia Monensis/ he substituted for it Alderi. 

 I am rejoiced at being thus able to cut the Gordian 

 Knot by perpetuating a name endeared to all lovers of 

 British marine zoology. Philippi at first called the pre- 

 sent species intermedia ; this he subsequently cancelled 

 in favour of marochiensis , under an erroneous impression 

 that the European species was Nerita marochiensis of 

 Gmelin (founded on the Nerita Maroccance of Chemnitz) , 

 said to inhabit Morocco, the West Indies, and Guiana. 

 Philippics mistake originated with Menke. Nor is our 

 species N. castanea of Lamarck, as Bouchard-Chante- 

 reaux supposed, nor N.pulcheUa of Hisso, to which Loven 



